We purchased an 825 a little over a month ago and have about 12 days on it so far. From the start I planned on upgrading to Lithium and adding an inverter. The 825 is small, so space is tight, but it worked. The main system components are as follows:
2x Lion Energy Safari UT 1300 Lithium batteries, 105 Ah each, for a total of 210 Ah
Victron 12-12 / 18 DC-DC charger
Victron BMV-712 Monitor
Xantrex Freedom XC 2000 watt inverter / charger
The entire system fits in the battery compartment.
The only wires added beyond the battery compartment are (a) 110v going from the shore plug to the inverter and back to the Progressive Dynamics Load Center, and (b) a new 8 awg wire from the front bench electrical distribution area to the battery compartment. I struggled to find a way to run these and ended up drilling through the bench seat walls and running the wires through a chase that is below the table support. Although wires run under the floor as built, I could not find a way to reasonably do the same. I presume all of the wire and other runs are done by Lance before the floor goes in. The chase is out of the way and doesn't look out of place in my view.
I also added 2 vents to the battery compartment where the intake fans are on the inverter so it can pull air into the compartment. I left the old battery vents to allow some outside air flow.
The way it is set up, I put a switch on the little panel inside the battery compartment door. To turn on the inverter I just open the door and flip that switch. The panel also has the BMV-712, but I will typically use the bluetooth to view it.
In the front compartment I removed the BlueSea ACR. The incoming wire from the truck plug now goes to the DC-DC Charger. With the standard 8 awg running from the truck battery to the DC-DC charger it pulls just under 23 amps at the truck battery and per the BMV is pushing 19 amps into the house batteries (actually 1 amp above the charger's rating).
A before-and-after wiring diagram and some photos are attached.Attachment 367113Attachment 367116Attachment 367114Attachment 367115Attachment 367117